The Linux kernel verifier incorrectly interpreted the arguments for the bpf_xdp_store_bytes helper, treating a data store operation in a read‑only BPF map as a writable access. This caused legitimate BPF programs that need to write to read‑only maps to be rejected by the verifier until the bug is fixed. The patch corrects the helper prototype to match bpf_skb_store_bytes, restoring proper validation and allowing the programs to load again.

The issue exists in any Linux kernel that implements the buggy bpf_xdp_store_bytes prototype until the kernel is updated with the CVE-2026-45886 fix. It applies to all vendor distributions shipping the affected kernel source. Specific version ranges are not listed in the advisories; users should refer to kernel changelogs that include the patch.

Because the flaw only affects verification of BPF helper arguments, there is no known direct exploit path. The EPSS score is less than 1% and the vulnerability is not listed in CISA KEV. The CVSS score of 5.5 indicates moderate severity, primarily resulting in operational disruption where BPF programs are denied rather than a privilege escalation or memory corruption. The likely attack vector is the local execution of a BPF program that attempts to write to a read‑only map, which is then blocked by the verifier. No evidence indicates the problem can be leveraged beyond preventing successful BPF program loading.